In the toad retinal pigment epithelium (RPE) eyecup, it was demonstrated that the interphotoreceptor retinoid-binding protein (IRBP) promotes the RPE's conversion of radiolabeled 11-cis retinyl ester to 11-cis retinal. IRBP was successfully photoaffinity-labeled with tritiated retinoic acid, and the photoaffinity labeled IRBP was used to demonstrate the presence of a putative cell surface receptor for IRBP in RPE cells in culture. Binding affinities of rat B cell and human B cell heat shock protein (hsp) 70s to analogs of rat IRBP peptide 1181-1191 were demonstrated to be correlated with the pathogenicity of the peptides in the Lewis rat. An examination of the mechanism of photoreceptor cell death in the vitiligo mouse model of retinal degeneration showed that an apoptotic mechanism is involved. It was also shown that the expression of TRPM-2 (Clusterin) is elevated in vitiligo retinas, beginning at one week in the RPE and later (by 12 weeks) in the neural retina. Drosophila retinoid- and fatty acid-binding protein (DRBP) wa localized to the cone (Semper) cells in the Drosophila compound eye. DRBP levels were lower in the eyes of flies that were deprived of carotenoids, suggesting that DRBP is relevant to retinoid handling in the Drosophila eye.